Rake task to archive old migrations

archive_old_migrations.rake

namespace :db do
  namespace :migrations do
    task :archive do
      considered_old = 60 # how many days ago is considered old enough
      puts "Looking for migrations older than #{considered_old} days"
      db_path = File.join(Rails.root, "db/")
      migrations_path = File.join(db_path, "migrate/")
      old_migrations_path = File.join(db_path, "old_migrations/")

      files = Dir[File.join(migrations_path, "/*.rb")]
      moved = []
      files.each do |m|
        timestamp = m.match(%r{/(\d{14})_})[1] rescue nil
        next unless timestamp
        date = DateTime.strptime(timestamp, "%Y%m%d%H%M%S")
        if date <= Date.today - considered_old
          filename = File.basename(m)
          puts "Archiving #{filename}"
          FileUtils.mkdir_p(old_migrations_path)
          FileUtils.mv(m, File.join(old_migrations_path, filename))
          moved << m
        end
      end
      
      if moved.count > 0
        puts "Moved #{moved.count} migrations to #{old_migrations_path}"
      else
        puts "No migrations older than #{considered_old} days found"
      end
    end
  end
end